I decided today to check the Outback over as I'm off the London on Tuesday. It also needed a clean, so the car got a good once over for the first time since I bought it. Everything was fine until I checked the tyres. Rear tyres were checked first and were absolutely spot on with the recommendations.
Front tyres which should have been at 2.0bar were at 3.9bar - yes 3.9bar - both of them. I checked with three gauges! I've lowered them to the correct level and again checked with all three gauges. I haven't drive the car since Friday afternoon and won't until Monday morning. Tyres look OK. Apart from feeling the road properly, and possibly worse fuel consumption (unlikely to make much difference!), I wonder what I should worry about???
I assume that the garage I bought the car from in November (I know I shouldn't have left it too long) did not check the tyres properly or the technician simply got it wrong big time. It is a Subaru dealer, but only a short time in the network.
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Has the mechanic misread 3.9 bars as 39lbs per square inch? Are they roughly equivalent?
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Phil
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I had under inflated tires on my new car, meant to be 33psi and they were all only 26.
Best thing to do is to check them regularly using the manufacturer data on the door or handbook.
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Has the mechanic misread 3.9 bars as 39lbs per square inch? Are they roughly equivalent?
3.9 bar = 56.6 psi (approx)
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L\'escargot.
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2 Bars is about 30 psi? Operator tried to put in 30 psi, misread the gauge and got the number wrong - could be. Happened to me once in Oman; servicing bods put in 3.0 bars instead of 30 psi and the car handled VERY strangely! I am suprised that you'rs didn't too!
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Well I am a little disappointed with the ride over road humps, but assumed it was just the 60-section tyres rather than the 65 in the Forester.
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3.9 bar is probably over the max allowable pressure for the tyres (marked on the sidewall). How many miles have you done - I'd expect them to quickly show wear in the centres and you can never recover that.
I usually find tyres are way out on new car - the exception being the Merc I have now, which was spot on all round. Our Jazz came with stupidly high pressures (mid 40's) but the dealer hasn't impoved in the 3 yrs since - a recent newish courtesy Jazz seemed very harsh and that had mid-40's pressures too.
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Just checked more closely - they're 55-section compared to 65 I was used to so little wonder I thought the ride was hardish. I also looked at the tread (I've done about 2,000miles since I got the car) and can't see anything wrong.
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Am I right in thinking dealers over-inflate the tyres of showroom cars to stop them looking soggy if they are standing for a while, and then re-adjust the pressure when they are sold?
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I think some dealers do over inflate to prevent the tyres going out of shape if the car will be standing for a while. I over inflate the tyres on my supra when it's not being used over the winter, although I only go up 45psi.
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In my experience you can never trust dealers to get tyre pressures right. My new BM 3 that I picked up the other week had pressures all over the place. They're right now, though, and will get checked, cold, on a good gauge, at home at least every week.
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This car couldn't have been standing still for long, as it had a reasonably high mileage for its age, although I am gradually bringing the average down.
The main difference in driving this morning was not the steering which felt relatively the same as before (the PAS makes it very light) but that a certain rattle from within the cabin at certain speeds over certain types of road surface has disappeared.
Also a very slight softening of the ride over sharp bumps.
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Does some local hooligan come along with their footpump and over-inflate the tyres during the night out of spite?
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L\'escargot.
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I had a conversation about this with a tech at my local independent when I had two new tyres in December. He said that they prefer to inflate tyres to about 250 kPa (36 psi) because this helps prevent premature wear on the edges. (My old front ones were showing signs of this on the inner edges but not the outer ones, so I'm inclined to blame it on speed cushions, but that's for another thread. In any case, the immediate problem was the screw in one of them.)
Anyway, I picked the car up that night and drove it the half-mile home. Took it out properly the next day and thought the steering felt a bit odd - jittery and over-responsive, and not in a good way. I checked the front tyres - the P6000s that had been on the back for 18 months - and the pressures were as I normally keep them, about 210 kPa. So I checked the new P6000s on the rear wheels and they were way over - something like 300 kPa (44 psi). I let them down again and the steering returned to normal. Now, obviously all four tyres have an influence on the car's handling and ride, but I was surprised how much difference the state of the rear tyres made to the way the wheel felt in my hands.
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BTW Espada III, did you know today (5th Feb) is Santa Agata's day? Or have you raised a glass already?
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The max pressure may be in the order of 60PSI so go to the dealer and get them to check the tyre wall for deformation and the tyre for roundness. Infalting to this pressure is not the problem it is running the tyres at this pressure that can do harm. Any doubt get them taken off and examine the inside for delamination. You must have been driving on ball bearing since you bought it. I used to train people in car craft by using 50 PSi to de-stabilise the car and make it break away easily.. Regards Peter
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The ride in the Aygo felt a bit hard and the steering a little too light when i first drove it. I checked the pressures and they were all 36 PSI which is correct with the handbook - but for high speed motoring. They recommend 34 for urban conditions. The car had been driven on the motorway when delivered, so delivery garage got the pressures spot on. Knowing we would be using it for urban journeys most of the time I reduced them to 34 and it now feels much better.
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36 PSI which is correct with the handbook - but for high speed motoring. They recommend 34 for urban conditions.
2lbs is neither here nor there - I doubt the average DIY gauge is that accurate, and the forecourt ones are all over the place.
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Espada III - I am today having new tyres fitted for my 2.5 Outback, 215/60 R16.
They were fitted with 55 profile when I bought 2nd hand, which is wrong! Check your service manual, but I believe all Outbacks ought to be 60, with R16 - perhaps less if you have 17 inch wheels.
Certainly a lower profile will increase noise a little and make the ride more firm.
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Unfortunately I have 17" wheels and 55-section tyres (I havejust checked) so no wonder I thought the ride was harsher than in the Forester. Ohhow I yearn for our old Forester with nice bouncy tyres and a soft ride. Mine is however better than the Volvo S80 I had a couple of years ago.
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Espada, Have you considered that the calibration of the workshops pressure guage might be inaccurate ? I met this once in Chesterfield when I was on a trip in a company pool vehicle. The gauge was so inacurate that I had to average out the pressures of the other three wheels and pump them all up to the same. If it's your own car then the backroom recommends that you carry a guage that you know is accurate.
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2lbs is neither here nor there - I doubt the average DIY gauge is that accurate, and the forecourt ones are all over the place.
That depends on the car, maybe its okay on a Ford Transit, but some sports cars eg Lotus Esprit, with ultra low profile tyres will really show a difference in handling at + or - 2 psi, and to be honest bI could probably tell even on my Audi for the front tyres.
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Thats a shocking difference Espada, it must have really effected the handling.
The fact is unless we all start using Nitrogen filling our tyres, the new trend for fitting lower profile tyres which need fairly high pressures unfortunately means we should check em regularly, every month max I'd say.
A work colleague of mine had a Volvo S40 with 40 profile tyres and didn't check the pressure for 10 months, only to find that one of the tyres on the front was so damaged by the under inflation it had to be replaced well before its time. Not to mention what could have happened on the motorway.
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the new trend for fitting lower profile tyres which need fairly high pressures..
Lower profile tyres run on the same pressure as higher profile. On a given car, the area of tyre in contact with the road remains constant regardless of the width, profile & diameter of the tyres.
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Weird thing is that there has been no noticeable difference in handling and a very minor improvement in ride. The only obvious difference (as I said above) is the rattle which has disappeared. The steering is perhaps very slightly heavier, but with the emphasis on very slightly.
I would have said that it was my gauge at fault, but I checked all four tyres with two pencil guages and with the digital gauge attached to my compressor and all three read 2.0bar on the rears and 3.9bar on the fronts.
What I did notice about my trip to London yesterday was that my economy on Shell V-Power was better than using BP regular unleaded. A full tank of Shell V-Power got me to London and 1/2 the way back at an average of 28.8mpg cruising at over 80mph. I got the same economy on BP but at no more than 75mph for half the return trip.
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